Two single-tube media, lactose-tryptone-lauryl sulphate broth (LTLSB) and lauryl-tryptose-mannitol broth were tested in parallel in a series of 1111 tests on water samples from a variety of sources.

LTLSB was found to be superior both in gas and indole production from Escherichia coli when incubated at 44 °C and is recommended as the most suitable single-tube confirmatory test for this organism.

Specific IgM antibody production in patients with serologically proven Mycoplasma pneumoniae infection by the complement fixation (CF) test was studied using a μ-capture ELISA. Sera from 79% of patients were found to be IgM positive. Patients could be divided into two groups relating to the amount of specific antibody produced. High levels of specific IgM (≥10 units) were more commonly found in younger patients. Seventy-six per cent of patients under the age of 20 produced relatively high levels of IgM compared to 35% of patients over the age of 20. In contrast, the number of patients who produced low or undetectable levels of IgM ( < 10 units) was found to increase with age. This trend was found to be significant which suggests that low or undetectable levels of IgM may be due to reinfection with M. pneumoniae. Specific IgM was found to appear in the serum at approximately 7 days after the onset of symptoms, peaking at between 10 and 30 days, and then falling to undetectable levels at an estimated 12–26 weeks post onset of symptoms. Twenty-eight per cent of acute-phase sera (CF titres < 256) from patients whose sera subsequently showed a fourfold or greater rise in M. pneumoniae CF antibody titre were IgM positive. Thus using μ-capture ELISA a diagnosis of M. pneumoniae infection may often be made more rapidly than by the complement fixation test.

Two waves of vomiting and/or diarrhoea affected approximately 215 of the 715 passengers on a Caribbean cruise ship. The outbreak was independently associated with eating cream-filled pastries at two separate meals. Staphylococcus aureus phage type 85/+ was isolated from cases and pastry cooks, but not from controls. This is the first well-documented outbreak of staphylococcal food poisoning on a cruise ship.

Following isolation of Legionella pneumophila from a special dental station water circuit, used primarily to cool high-speed dental drills which produce fine aerosols, a case finding and environmental survey was undertaken. Widespread colonization of the dental stations was found and the results suggested that amplification of the background levels of L. pneumophila was taking place within the stations. However there was no evidence for transmission causing human infection.

The incidence of hospital-diagnosed human hydatid disease acquired in the UK was estimated from a survey based on Hospital Activity Analysis data for the period 1974–83. The average annual incidence in Wales was 0·4 per 100000 population compared with 0·02 per 100000 in England. Within Wales, Powys, and particularly Brecknock, had the highest incidence (7 per 100000 per year). Compared with the period 1953–62, the average annual incidence for Wales fell by half (from 0·8 to 0·4 per 100000 per year), but in Powys the incidence did not decline, and in Brecknock and Montgomery there was a marginal increase. In comparison with 1953–62, the age-specific incidence in Wales and Powys decreased in each age group with the notable exception of children < 15 years of age. This finding emphasizes that transmission of Echinococcus granulosus to humans is still occurring at hyper-endemic levels in parts of England and Wales and that control efforts should be intensified.

Food poisoning caused by Clostridium botulinum toxin A occurred in Japan. Eleven (31 %) of 36 patients from 14 different areas died of botulism. Most of the patients had eaten commercial fried lotus-rhizome solid mustard without heating. The food, which implicated one of the special local products used for gifts in Kumamoto, was found to have been produced by a manufacturer in Kumamoto prefecture.

In Fukuoka prefecture, two of three patients died on days 4 and 8 after eating the food; they had typical symptoms of botulism. A total of 42 packages of the food bought as gifts was collected from different districts in Fukuoka prefecture for examination for both organism and toxin. Thirteen of these (31%) were contaminated with the organism, and in 11 (26%) a small amount of toxin A had been produced.

Two enrichment methods were compared for their ability to recover Clostridium difficile from stool samples. One method used selective enrichment in an antibiotic-containing broth followed by detection with a latex particle agglutination (LPA) reagent. The other used enrichment in a non-selective broth following treatment of the specimen with alcohol. With clinical specimens enrichment culture was significantly more successful at detecting C. difficile than direct plating. Alcohol shock enrichment was twice as effective as direct culture, while selective broth enrichment was three times more effective. The use of LPA for screening selective enrichment broths for C. difficile should prove a cost-effective measure as only positive broths (about 20%) require subculture for confirmation.

Human immunodeficiency virus antigen (HIV-ag) was determined by enzyme immunoassay (EIA) in HIV-antibody (anti-HIV) positive as well as pre-anti-HIV seroconversion sera and the results analysed according to stage of infection, risk group, age and geographic origin. Eleven (19%) of 58 homosexual men tested showed HIV-ag in a serum taken 3–4 months before or one at the time of anti-HIV seroconversion. In another eight (14%) HIV-ag persisted after seroconversion and half of them developed AIDS or AIDS-related complex (ARC) in contrast to none of the other 50 anti-HIV seroconversions. Two (13%) of 16 haemophiliacs tested had HIV-ag only in the first anti-HIV seropositive sample. HIV-ag was present in 86% (30/35) of Dutch homosexual men with AIDS, in 32% (7/22) of men with ARC and in 17% (24/145) of men with persistent generalized lymphadenopathy (PGL) or without symptoms. Three percent (2/60) of sera of asymptomatic i.v. drug users from Amsterdam were HIV-ag positive. Ten percent (1 of 10) of sera from Central Africans with ‘Slim Disease’ were HIV-ag positive. Among infected children from the USA or Europe 89n100% (8/9 and 2/2) of AIDS cases, 67–100% (6/9 and 3/3) of children with ARC and 75% (3/4) of asymptomatic children were HIV-ag positive. The HIV-ag EIA appears to be able to identify HIV infection earlier than the available anti-HIV assays in a significant number of cases. Since persistence of HIV-ag, except possibly in African cases, is strongly associated with clinical deterioration, HIV-ag appears to be a suitable marker for, independent of their clinical status, selecting individuals for antiviral therapy and also for monitoring the efficiency of such therapy.

The herd incidence of confirmed Mycobacterium bovis infection in cattle in the south-west of England has been approximately ten times that of the remainder of England and Wales; this greater incidence has been attributed to infection from badgers. The incidence of herds with only non-visible lesioned tuberculin test reactors, from which M. bovis was not isolated, has also remained higherin the south-west region.

The incidences of these latter unconfirmed incidents were compared in parishes in the south-west region in which M. bovis in cattle had been confirmed, and those where M. bovis had not been confirmed, for the period 1979–83. This analysis was carried out both for those parishes in which herds had been subjected to annual tuberculin testing and for those subjected to biennial tuberculin testing. The incidence of unconfirmed incidents was significantly higher in parishes in which confirmedincidents had occurred, and this difference was found in both the annual and biennially tested parishes. The relative risks for the incidence of unconfirmed incidents in annually and biennially tested parishes were 1*89 and 2–56, respectively. The incidence of unconfirmed incidents in biennially tested parishes was lower than in annually tested parishes.

The incidence of non-specific tuberculin test reactor herds was estimated from tuberculin test results in the eastern region of England during a period when tuberculosis was not confirmed in cattle. A comparison of this incidence and that of unconfirmed incidents in the south-west region suggests that approximately 70% of the unconfirmed incidents in the south-west were related to exposure to M. bovis.

The results of the analyses indicate that unconfirmed incidents cannot be completely ignored in epidemiological analyses and studies of bovine tuberculosis in the problem areas of the south-west region of England.

Hitherto, detection of lymphoproliferative disease virus (LPDV), a C-type retrovirus of turkeys, has proved difficult since no tissue culture or serological assay has been available. Development of serological tests has been hampered by the problems of raising virus-specific antisera. An indirect enzyme-linked immunosorbent assay (ELISA) is reported, using a viral antiserum raised with bromelain-digested virus.

The assay specifically detected purified virus at a concentration of 250 ng/ml or greater. In an experiment to detect virus in plasma from turkeys over a period of 4 weeks following LPDV infection, ELISA results correlated closely with the viral reverse transcriptase activity. Both assays were of similar sensitivity and detected small amounts of virus in high-speed pellets of turkey plasma. Evidence is presented indicating that LPDV-infected or hyperimmunized turkeys do not produce readily detectable circulating viral antibodies. In reciprocal ELISA tests, using antibodies to group-specific antigens of other avian retrovirus groups (avian sarcoma-leukosis (ASLV) and reticuloendotheliosis (REV)) no antigenic cross-reaction was found between LPDV, ASLV and REV.

Tropical ulcer is a disease found most commonly in the tropics, although the disease is not confined to those areas. Young children are affected most frequently and the disease is thought to be a polymicrobial infection with fusobacteria, aerobic microorganisms and spirochaetes each playing a role. The fusobacteria have been reported on smears but have not been cultured thus far. We report the isolation and culture of these organisms from 46 ulcers and have also demonstrated the same organisms in skin biopsies from these lesions.

Strains of Haemophilus influenzae isolated from patients in N.E. Scotland between 1983 and 1986 have been subtyped by sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE) of whole-cell polypeptides. Gels were stained with Coomassie blue and polypeptide profiles were analysed using the Dice coefficient of similarity.

Type b strains were all closely related, the 19 strains analysed being grouped at a 90% similarity level into one large (13 strains) and one small (3 strains) cluster with 3 strains being ungrouped. Thirty-six non-typable, epidemiologically unrelated strains were subtyped; one pair of strains had indistinguishable polypeptide profiles. The polypeptide profiles of the remaining strains showed much heterogeneity, although groups of strains isolated from the same patient over short periods showed indistinguishable profiles.

Cases of African swine fever (ASF) confirmed in the laboratory in 1985 and 1986 and other data obtained since 1984, in particular an extension of the serological survey of free-ranging domestic pigs undertaken from 1981 to 1984, are presented to give an updated survey of the ASF situation in Malawi and a revised estimate of the ASF enzootic area. Evidence is presented that the area may include some border areas in Dedza and Ntcheu districts and may be expanding in some localities.

Among 30 strains of leptospires isolated from samples of sewage taken before and during treatment at two sewage plants in England, only one appeared to belong to Leptospira interrogans, the species that comprises the leptospires that are pathogenic to man and animals. That strain, Compton 746, was isolated from settled sewage, before treatment at a treatment plant that deals mainly with human sewage. It was shown serologically to belong to serogroup Tarassovi and appears to represent a new serovar that has been named mogdeni after the name of the sewage plant, Mogden, from which it was isolated.

A cross-sectional serological survey of domestic animals in West Malaysia revealed that 25·5% of the animals examined had agglutinating antibodies to one or more antigens belonging to Leptospira interrogans. Significant prevalence of infection was observed in cattle (40·5%), buffaloes (31%) and pigs (16%). The Sejroe serogroup was shown to be the principal one involved in cattle and buffaloes, and to a lesser extent the Tarassovi and Pomona serogroups. Evidence of infection in domestic animals by strains bearing the other seven antigens appeared insignificant and was indicative of sporadic infection. A majority of the large (semi-intensive) cattle and buffalo farms demonstrated a high prevalence of leptospiral infection. In both species of domestic animals mentioned above, the prevalence of infection was significantly higher (P = 0·01) in the semi-intensive farms than in the smallholdings. Amongst cattle, the droughtmasters had the highest prevalence whilst the Kedah-Kelantan (an indigenous breed) had the lowest prevalence of leptospiral infection. In general, the temperate breeds of cattle had a significantly (P = 0·01) higher prevalence of infection than local breeds. Leptospiral infection in goats and sheep was shown to be sporadic, and the Pomona serogroup was the principal leptospiral serogroup involved in these small ruminants. The prevalence of infection in pigs was observed to decline during the study period, and it is suspected that pigs in West Malaysia are the maintenance host for serovar pomona whilst cattle are the maintenance host for serovar hardjo. Overall, it appears that domestic animals in Malaysia will play a bigger role in the epidemiology of leptospiral infection with the advent of sophisticated farming.

Investigations using a liquid-phase blocking sandwich enzyme-linked immunosorbent assay (ELISA) for the measurement of antibodies against foot-and-mouth disease virus (FMDV) in sera from sheep and from cattle are reported, and results compared with those obtained by virus neutralization (VN) tests.

Serum antibody titres in sheep after primary vaccination and in cattle challenged with a natural aerosol after vaccination were similar by ELISA and VN. However, the antibody levels detected in sera of cattle during early infection and of vaccinated cattle after intradermolingual challenge were clearly greater by ELISA than by VN.

The ELISA titres in cattle sera following synthetic peptide vaccination indicated some relationship to protection and were clearly different from those recorded by VN. On the other hand, the antibody levels following conventional vaccination showed that ELISA and VN titres in cattle sera were related to protection. Although there was a good agreement between the ELISA antibody titre and protection for the four vaccines used, by VN the titre which afforded protection varied depending on the vaccine used.

The ELISA was considered therefore to be more reliable than the VN and may prove useful for evaluating the immunological response of animals following infection and following vaccination.

A high percentage of non-typable (NT) Staphylococcus aureus strains was isolated in Spanish hospitals during 1984 and 1985. Several alternative methods of typing were employed to study these isolates. These were: phage-typing at 1000 × RTD, phage-typing after heat-treatment (48 °C), thermal shock (56 °C), reverse-typing and induction of additional phages. Using these methods the number of NT isolates was reducedby 60%. Best results were obtained with heat-treatment. Additional phages and reverse-typing were also useful.

A scheme for the study of outbreaks and sporadic cases caused by NT strains is proposed using the methods described.

Candida albicans has recently been described as a cause of nosocomial infection. This paper reports four further outbreaks occurring over a 12-month period in England. There were 13 systemic cases and 6 deaths. The outbreaks were defined by morphotyping andthe new technique of immunoblot fingerprinting. Controi of the outbreaks was produced bythe implementation of strict cross-infection control policies without recourse to systemic chemoprophylaxis.

A field strain of influenza A (H3N2) virus isolated in embryonated eggs during the 1984–5 influenza outbreak (A/Finland/13/85E) was compared in an antigenic analysis with virus from the same clinical specimen isolated in MDCK cell cultures (A/Finland/13/85M). The M-virus appeared to be more sensitive to haemagglutination-inhibiting antibodies against heterologous viruses than did the Evirus. The results of propagation and plaque purification experiments support the hypothesis that a single clinical specimen may consist of distinct antigenic variant subpopulations promoted selectively by the host during isolation procedures. Receptor-binding properties are discussed as a possible explanation for this selectivity.

A set of 471 paired sera consisting of pre-epidemic and post-epidemic specimens taken from the same subjects in 1984–5 was studied for haemagglutinationinhibiting antibodies to six influenza A (H3N2) virus strains, including the E-virus and the M-virus from A/Finland/13/85. Of the antigens used, the M-virus detected significant antibody increases more frequently than did the E-virus (10·0 v. 5·9%). The superiority of the M-virus may rest primarily in its ability to pick out anamnestic antibody responses. Irrespective of this cross-reactivity, preepidemic antibody to the M-virus was fairly well associated with protection. In the set of sera (230 specimens) collected in summer 1985 to represent different age groups, the antibody status against the M-virus was significantly better than the status against the E-virus. The results suggest that, at least in some instances, antibody to MDCK-grown virus is a more accurate indicator of the immune status of a community than antibodies to egg-grown virus variants.

The one-point MCA method is very simple to perform nnd useful as a screening test in diagnosing leptospirosis in routine clinical laboratories.

The kit, sensitized with six serovars occurring in Japan, was also useful in detecting serum antibodies of patients with leptospirosis in China.